+1 for Craigslist. Pro tip: wherever you end up listing get your car detailed if it’s not already immaculate and take lots of photos inside and out. And if you’ve kept your maintenance records make sure you mention that’s available for buyers to review.
In the Bay Area, try deals on wheels in Santa Clara. For a nominal fee, they’ll manage the sale of your vehicle. Alternatively, they will buy it from you as well, typically at or higher than blue book.
Try AAA CarConnect. You pay a small fee up-front ($150 or something) and they create listings for you and act as a facilitator. I personally had a good experience using this service. They can handle title transfers and registration in-house as well.